To ensure that the chicken cooks quickly and evenly, thinly slice it into small, even pieces.
To make the marinade, put the minced lemongrass, garlic, ginger, soy sauce, sesame oil, lime juice, black pepper, and salt in a bowl.
Add the chicken to the marinade and toss to coat it completely. For the flavours to develop, let it sit for ten to fifteen minutes.
Get the veggies ready: Shred the lettuce, julienne the carrot, cut the green onions and cucumber, and prepare the cilantro and mint while the chicken marinates.
To cook the chicken, put a large skillet over medium-high heat and add one tablespoon of frying oil. In a single layer, add the marinated chicken.
Sear: Cook, stirring periodically, until the chicken is cooked through, golden brown, and fragrant, about 5 to 7 minutes. The internal temperature of the chicken should be 165°F, or 74°C.
Cool slightly: Take the chicken off of the hob and give it some time to cool. This keeps the rice paper from getting too mushy when put together.
Make the rice paper softer: Pour warm water into a big shallow dish. One rice paper wrapper should be dipped in water for five to ten seconds, or until it becomes flexible. Avoid soaking it too much.
Put the softened wrapper on a spotless, somewhat moist surface and add the filling. Spread the lower third with lettuce, a tiny bit of carrot, cucumber, green onion, cilantro, mint, and a few pieces of lemongrass chicken.
Fold: Like a burrito, fold the bottom edge over the filling, fold both sides inward, and then roll tightly toward the top.
Repeat: Proceed with the remaining filling and wrappers. To prevent them from sticking together, keep the completed rolls apart.
If preferred, cut the buns in half diagonally before serving. Place them on a platter with lime wedges and sweet chilli sauce.